1. Field of the Invention
The present invention relates to a semiconductor memory device, and more particularly to a structure of a semiconductor memory device allowing an efficient column selection.
2. Description of the Background Art
With the increase in capacity of semiconductor memory devices in recent years, it has become common that a memory array provided in a semiconductor memory device is divided into blocks of memory cells (hereinafter referred to as a memory mat) and a memory mat is further divided into a plurality of sub blocks.